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C-S-H晶种与硫酸铝作用下PC-CSA的凝结硬化性能 被引量:1
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作者 卢子臣 MOHAMMAD Mahadi Hasan +2 位作者 张立恒 贾亚运 孙振平 《建筑材料学报》 北大核心 2025年第2期95-102,共8页
利用凝结时间、抗压强度等测试,系统评价了水化硅酸钙(C-S-H)晶种与硫酸铝(AS)对硅酸盐-硫铝酸盐复合胶凝体系(PC-CSA)凝结硬化性能的影响,并通过水化进程、水化产物和微观结构分析探究其内在作用机理.结果表明:C-S-H晶种与AS均能显著缩... 利用凝结时间、抗压强度等测试,系统评价了水化硅酸钙(C-S-H)晶种与硫酸铝(AS)对硅酸盐-硫铝酸盐复合胶凝体系(PC-CSA)凝结硬化性能的影响,并通过水化进程、水化产物和微观结构分析探究其内在作用机理.结果表明:C-S-H晶种与AS均能显著缩短PC-CSA的凝结时间;复掺C-S-H晶种与AS显著促进了PC-CSA中硅相矿物的水化,提高了微观结构的致密性,提升了PC-CSA的抗压强度;当单掺AS时,PC-CSA中水化产物C-S-H的成核与长大过程均受抑制,而C-S-H晶种的加入通过提供成核位点,减缓了对水化产物C-S-H成核过程的抑制效果,促进了硅相矿物的反应,有助于解决喷射混凝土速凝与早强不协调的问题. 展开更多
关键词 喷射混凝土 c-s-H晶种 硫酸铝 硫铝酸盐水泥 水化特性 孔结构
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纳米C-S-H晶种对水泥基材料凝结硬化过程的影响 被引量:2
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作者 康阳阳 夏艳晴 +3 位作者 张雨晴 梁志远 唐涛 张柯莹 《新型建筑材料》 2025年第4期82-89,108,共9页
纳米C-S-H晶种在较低掺量下便能显著提高水泥基材料的早期强度,并且不会对长期性能造成不利影响,因而成为近期的研究热点。然而,目前仍未有研究系统阐述纳米C-S-H晶种对水泥基材料凝结硬化过程的影响及其作用机理。从纳米C-S-H晶种概述... 纳米C-S-H晶种在较低掺量下便能显著提高水泥基材料的早期强度,并且不会对长期性能造成不利影响,因而成为近期的研究热点。然而,目前仍未有研究系统阐述纳米C-S-H晶种对水泥基材料凝结硬化过程的影响及其作用机理。从纳米C-S-H晶种概述,纳米C-S-H晶种对水泥基材料水化进程、微观结构和性能的影响,纳米C-S-H晶种在水泥基材料中的作用机理和纳米C-S-H晶种与其它混凝土外加剂的协同作用4个方面出发,系统总结并分析了纳米C-S-H晶种在水泥基材料中的研究现状,旨在为外加剂的应用提供一定的参考。 展开更多
关键词 纳米c-s-H晶种 水化进程 水化产物 孔结构 抗压强度 作用机理
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C/SiC与TC4层合结构的斜侵彻破坏行为和机理
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作者 程然 李涛 朱志武 《纤维复合材料》 2025年第2期12-22,38,共12页
为研究复合材料(C/SiC)与钛合金(TC4)层合结构在斜侵彻过程中的细观结构响应、破坏模式、失效机理以及其与侵彻速度和倾角的依赖关系,开展了球形弹丸斜侵彻(速度和倾角分别为350~550 m/s和30°~60°)该结构的试验和数值仿真研... 为研究复合材料(C/SiC)与钛合金(TC4)层合结构在斜侵彻过程中的细观结构响应、破坏模式、失效机理以及其与侵彻速度和倾角的依赖关系,开展了球形弹丸斜侵彻(速度和倾角分别为350~550 m/s和30°~60°)该结构的试验和数值仿真研究。构建了包含微孔洞、SiC基体、横向/纵向纤维束的C/SiC复合材料细观模型,并利用哈希准则对复合材料进行损伤判定。侵彻过程中,C/SiC对冲击波的强烈衰减作用导致靶板背面未出现层裂,C/SiC前板中部出现分层和纤维断裂并形成向背面倾斜扩展的裂纹,弹丸与TC4后板接触后该板才出现显著弯曲变形继而被击穿。该层合结构的侵彻破坏模式包括:纤维束断裂、微孔洞塌陷、复合材料内部分层、C/SiC与TC4界面分层。随着侵彻速度的增大,剪应力的增加导致C/SiC复合材料的破坏模式从分层向纤维剪切断裂转变,斜裂纹的倾角增加,扩展距离增长。随着侵彻倾角的增大,弹丸面外方向的速度分量降低,TC4后板的弯曲变形量减少,C/SiC与TC4界面分层裂纹的起裂时刻延迟,但分层面积增加。 展开更多
关键词 c/sic与Tc4层合结构 斜侵彻 破坏模式 失效机理
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LINEAR ACTIVE STRUCTURES AND MODES (Ⅱ) —DISCRETE SYSTEMS AND BEAMS
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作者 王永刚 龚靖School of Civil Engineering and Mechanics +10 位作者 Xi'an Jiaotong University Xi'an 710049 P.R.China Department of Civil Engineering Northeast China Institute of Electric Power Jilin 132012 P.R.China 张景绘School of Civil Engineering and Mechanics Xi'an Jiaotong University Xi'an 710049 P.R.China 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第8期854-862,共9页
The basic concepts about the active structures and some attributes of the modes were presented in paper “Liner Active Structures and Modes]( I) ". The characteristics of the active discrete systems and active be... The basic concepts about the active structures and some attributes of the modes were presented in paper “Liner Active Structures and Modes]( I) ". The characteristics of the active discrete systems and active beams were discussed, especially, the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-storeyed building with sensors and actuators. The concept of the adjoint active structure was extended from the discrete systems to the beams that were the representations of the continuous structures. Two types of beams with different placements of the measuring and actuating systems were discussed in detail. One is the beam with the discrete sensors and actuators, and the other is the beam with distributed sensor and actuator function. The orthogonality conditions were derived with the modal shapes of the active beam and its adjoint active beam. An example shows that the variation of eigenvalues with feedback amplitude for the homo-configuration and non-homo-configuration active structures. 展开更多
关键词 I) ". The characteristics of the active discrete systems and active beams were discussed especially the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-s
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C-S-H/PCE纳米复合材料的制备及其对水泥早期水化的影响
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作者 阴钰娇 吴飞 +1 位作者 周文强 何殿伟 《无机盐工业》 北大核心 2025年第9期66-72,共7页
为解决传统粉煤灰混合水泥砂浆早期强度发展缓慢、孔隙结构粗化等问题。通过共沉淀法合成了聚羧酸盐改性水化硅酸钙(C-S-H/PCE)纳米复合材料,并采用多种表征对其结构进行分析。深入探究其对粉煤灰混合水泥砂浆早期力学性能、孔隙结构、... 为解决传统粉煤灰混合水泥砂浆早期强度发展缓慢、孔隙结构粗化等问题。通过共沉淀法合成了聚羧酸盐改性水化硅酸钙(C-S-H/PCE)纳米复合材料,并采用多种表征对其结构进行分析。深入探究其对粉煤灰混合水泥砂浆早期力学性能、孔隙结构、水化动力学和水化产物的影响。结果表明:掺加C-S-H/PCE能够有效提高砂浆的早期抗压强度,且其抗压强度增长率与C-S-H/PCE掺量成正比;随着养护龄期的延长,抗压强度增长率减缓;C-S-H/PCE能够显著降低砂浆试样的孔隙率,并减小砂浆中的大孔比例,从而起到提高水泥砂浆的致密性,细化孔隙结构的作用;C-S-H/PCE能够促进水泥浆体的早期水化,提高浆体的早期水化程度且C-S-H/PCE掺量越高,促进效果越明显;C-S-H/PCE不仅有效促进了水泥生成更多的水化产物,加速了整个水化进程,而且这一过程并未改变水化产物的种类组成,确保了水泥性能的稳定性与可控性。未来研究可进一步聚焦于优化C-S-H/PCE的制备工艺,探索其在不同种类水泥及掺合料体系中的适用性,以及其对水泥基材料长期耐久性的影响机制。同时,结合先进的计算模拟技术,深入揭示C-S-H/PCE纳米复合材料与水泥基体间的相互作用机理,为开发高性能、长寿命的水泥基材料提供理论基础和技术支撑。 展开更多
关键词 c-s-H 水泥水化 孔隙结构 水化产物
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基于分布式C/S结构的烟草智能生产自动化控制系统设计
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作者 樊尉廷 马俊宽 +1 位作者 樊海峰 邓家强 《信息技术》 2025年第4期174-179,共6页
为了满足烟草企业控制系统的智能化和自动化需求,设计一种基于分布式C/S结构的烟草智能生产自动化控制系统。采用三层C/S结构,将自动化控制系统划分为表示层、功能层和数据层三个部分,通过工作流程、冗余控制、同步技术、切换要求和数... 为了满足烟草企业控制系统的智能化和自动化需求,设计一种基于分布式C/S结构的烟草智能生产自动化控制系统。采用三层C/S结构,将自动化控制系统划分为表示层、功能层和数据层三个部分,通过工作流程、冗余控制、同步技术、切换要求和数据更新五个方面设计硬件系统。采用PID控制器作为PLC的系统运行方式,联合人工蜂群(Artificial Bee Colony,ABC)算法和BP神经网络构建ABC-BP-PID控制器,获取最优PID控制器输出,调节系统参数,实现烟草智能生产自动化控制。实验结果表明,所提方法在控制中的跟踪性、抗干扰性和鲁棒性较强。 展开更多
关键词 分布式c/s结构 烟草智能生产 人工蜂群 PID控制器
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Effect of C/S Ratio on Morphology and Structure of Hydrothermally Synthesized Calcium Silicate Hydrate 被引量:12
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作者 何永佳 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第4期770-773,共4页
The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics... The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics of C-S-H samples were analyzed by XRD, IR and SEM. The experimental results showed that the d-spacing of (002), (110) and (020) decreased, the d-spacing of (200) increased, and the d-spacing of (310) varied randomly, the polymerization of silica tetrahedra of C-S-H decreased, and morphology of C-S-H samples varied from sheet shapes to long reticular fibers as C/S ratio increased. 展开更多
关键词 calcium silicate hydrate c/s ratio MORPHOLOGY structure hydrothermal synthesis
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A welding document management software package based on a Client/Server structure 被引量:4
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作者 魏艳红 杨春利 王敏 《China Welding》 EI CAS 2003年第1期72-77,共6页
According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software pa... According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software package can be used in a Limited Area Network (LAN) with 4 different levels of authorities for different users. Therefore, the welding documents, including DWPS (Design for Welding Procedure Specifications), PQRs (Procedure Qualification Records) and WPS (Welding Procedure Specifications) can be shared within a company. At the same time, the system provides users various functions such as browsing, copying, editing, searching and printing records, and helps users to make decision of whether a new PQR test is necessary or not according to the codes above as well. Furthermore, super users can also browse the history of record modification and retrieve the records when needed. 展开更多
关键词 c/s structure welding procedure qualification DATABAsE LAN
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Electronic Structure and Optical-absorption Properties of C-, N-, and S-doped BiOCl: the First-principles Calculations 被引量:1
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作者 YAO Wen-Zhi YAO Jian-Bin +1 位作者 ZHANG Xia MA Ya-Hao 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2019年第4期509-523,共15页
Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effec... Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance. 展开更多
关键词 BiOcl c N s DOPING the FIRsT-PRINcIPLEs electronic structures VIsIBLE light absorption
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Effect of Polymer on Morphology and Structure of Calcium Silicate Hydrate Prepared via Precipitation Method 被引量:3
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作者 吕林女 PING Bing +3 位作者 何永佳 HE Liu WU Xi HU Shuguang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第3期504-506,共3页
The effects of polyaerylamide (PAM) and polyvinyl alcohol (PVA) on morphology and structure of calcium silica~ hydrate with C/S 1.0-1.7 prepared via precipitation in solution were investigated by XRD, FT-IR and TE... The effects of polyaerylamide (PAM) and polyvinyl alcohol (PVA) on morphology and structure of calcium silica~ hydrate with C/S 1.0-1.7 prepared via precipitation in solution were investigated by XRD, FT-IR and TEM techniques. The results show that incorporation of the polymers decreased the order degree, increased the interlayer spacing and disturbed the layered stacking of C-S-H. Interlayer spacing expansion depended on C/S ratios and type of polymer. Interlayer spacing expansion had a minimum at C/S 1.0 and a maximum at C/S 1.3 and 1.5. Interlayer spacing expansion of PAM was bigger than that of PVA with the same C/S. C-S-H added with PVA mainly exhibited foil-like and fibrillar morphology. The fibrils were of variable length from a few tens of nanometers to a few hundreds of nanometers. Fibrils or foils seemed to be longer in the presence of PVA. 展开更多
关键词 c-s-H MORPHOLOGY structure POLYAcRYLAMIDE polyvinyl alcohol
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SYNTHESIS AND STRUCTURE OF COMPLEX(PPh3)_2Ni[S_2C=C(CN)_2]
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作者 Zi Xiang HUANG Shao Fang LU Jian Quan HUANG Jin Ling HUANG State Key Laboratory of Structural Chemistry and Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第12期1023-1024,共2页
(PPh_3)_2Ni(i-mnt),(i-mnt=S_2C=C(CN)_2),Mr=613.43,monoclinic,Pn,a=9.167(3),b=10.872(3), c=18.209(7) ,β=101.46(3)°,V=1779(1) ,Z=2,Dc=1.15 g/cm^3,λ(Moka)=0.71069 ,μ=7.67 cm^(-1), F(000)=648,T=296K,final R=0.060,... (PPh_3)_2Ni(i-mnt),(i-mnt=S_2C=C(CN)_2),Mr=613.43,monoclinic,Pn,a=9.167(3),b=10.872(3), c=18.209(7) ,β=101.46(3)°,V=1779(1) ,Z=2,Dc=1.15 g/cm^3,λ(Moka)=0.71069 ,μ=7.67 cm^(-1), F(000)=648,T=296K,final R=0.060,Rw=0.073 for 1909 observed reflections with Ⅰ≥3σ(Ⅰ).The complex adopts a square planar geometry as its coordination unit,the mean Ni-S and Ni-P distances are 2.216 and 2.221 ,respectivety. 展开更多
关键词 cN s2c=c sYNTHEsIs AND structure OF cOMPLEX NI PPH3
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Effect of solid solution modification on structure and properties of dicalcium silicate
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作者 王政 李家和 张玉珍 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第1期77-79,共3页
In the paper, dicalcium silicate (C2S) was modified to obtain higher performance, and the solutionizing pattern of BaSO4 in cement clinker was analyzed theoretically. According to experimental results, solutionizing o... In the paper, dicalcium silicate (C2S) was modified to obtain higher performance, and the solutionizing pattern of BaSO4 in cement clinker was analyzed theoretically. According to experimental results, solutionizing of BaSO4in cement clinker improved crystal plane distance of C2S as well as the relations of coordination. The performance tests show that the strength of C2S modified by BaSO4 changes and the reactivity of C2S increases significantly. 展开更多
关键词 solid solution crystal structure REAcTIVITY c2s
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Structures that should be Described in Higher-Symmetry, Centrosymmetric Space Groups. Part 1. The Disordered Structures of [(CH_3CH_2)_4N]_3{[(SCH_2CH_2S)MoS_3]_2Fe}, [(CH_3CH_2)_4N]_2{[S_2CN(C_2H_5)_2]_4Fe_4S_4} and [(CH_3CH_2)_4N]_3{[(SCH_2C
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《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2000年第6期405-410,共6页
关键词 scH2cH2s)Mos3 cH3cH2 c2H5 s2cN structures of Fe
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CRYSTAL STRUCTURE OF SEVEN-COORDINATE ZIRCONOCENE COMPLEX (CH_3C_5H_4) Zr(S_2CNBz_2)_3 (Bz=CH_2C_6H_5)
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作者 Zhi Qiang WANG Shi Wei LU +1 位作者 He Fu GUO Niag Hai HU 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第11期863-864,共2页
(CH_3C_5H_4)Zr(S_2CNBz_2)_3, Mr=987.55, space group P1, a=13.002(4), b=13.659(3), c=29.685(8); α=100.72(2)~o,β=97.23(2)~o, γ=105.36(2)~o; V=4909(2)~3, Z=4, Dc=1.34gcm^(-3), Mo-K(λ=0.71073A) radiation, μ=5.0cm^(-1... (CH_3C_5H_4)Zr(S_2CNBz_2)_3, Mr=987.55, space group P1, a=13.002(4), b=13.659(3), c=29.685(8); α=100.72(2)~o,β=97.23(2)~o, γ=105.36(2)~o; V=4909(2)~3, Z=4, Dc=1.34gcm^(-3), Mo-K(λ=0.71073A) radiation, μ=5.0cm^(-1), R=0.069, Rw=0.078 for 6100 reflections. The title complex has pentagonal bipyramid configuration in which the zirconium atom is coordinated by one CH_3C_5H_4 group and three bidentate dibenzyldithiocarbamate ligands. 展开更多
关键词 cH3c5H4 cRYsTAL structure OF sEVEN-cOORDINATE ZIRcONOcENE cOMPLEX s2cNBz2 Bz=cH2c6H5 ZR Bz
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ADJUSTMENT IN CHINA'S INDUSTRIAL STRUCTURE AND ITS FOREIGN TRADE
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作者 Liu Rixin,research fellow of theMacroeconomic Research Institute ofthe State Planning Commission 《China's Foreign Trade》 1996年第1期11-12,共2页
Of its total export volume,the proportion of China’s new andhigh technology products and highvalue-added products is extremelylow. Its pure technological exportrate is only 2 percent of the total.Therefore,along with... Of its total export volume,the proportion of China’s new andhigh technology products and highvalue-added products is extremelylow. Its pure technological exportrate is only 2 percent of the total.Therefore,along with thetransformation of the mode ofgrowth of China’s nationaleconomy, a corresponding growthmode transformation should takeplace in its foreign trade sector,and it is necessary to achieve asignificant change in its importand export product mix. 展开更多
关键词 mode ADJUsTMENT IN cHINA’s INDUsTRIAL structure AND ITs FOREIGN TRADE Us THAN ITs
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CRYSTAL STRUCTURE OF FIVE-COORDINATE ZIRCONOCENE COMPLEX CP_2ZrCl(S_2CNBz_2) (Bz=C_6H_5CH_2)
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作者 Zhi Qiang WANG Shi Wei LU +1 位作者 He Fu GUO Ning Hai HU 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第11期865-866,共2页
Cp;ZrCl(S;CNBz;) is a five-coordinate bent zirconocene in which the dibenzyldithiocarbamate is a bidentate ligand (Zr-Cl 2.549(1)A; Zr-C 2.489-2.533; Zr-S 2.667(1), 2.734(1); Zr-Cl-S1 137.6(1);; Zr-Cl-S2 73.... Cp;ZrCl(S;CNBz;) is a five-coordinate bent zirconocene in which the dibenzyldithiocarbamate is a bidentate ligand (Zr-Cl 2.549(1)A; Zr-C 2.489-2.533; Zr-S 2.667(1), 2.734(1); Zr-Cl-S1 137.6(1);; Zr-Cl-S2 73.3(1);). 展开更多
关键词 Bz=c6H5cH2 Zr cP cRYsTAL structure OF FIVE-cOORDINATE ZIRcONOcENE cOMPLEX cP2Zrcl Bz s2cNBz2 cH
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Crystal Structure of Phenol,2-[4(S)-4-Dihydro-4-benzyl-2-ozazolinyl]
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作者 罗梅 周仕明 +3 位作者 张家海 庞文民 尹浩 胡克良 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第6期947-949,共3页
The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenz... The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenzonitrile with optically active amino alcohol in chloroben-zene under dry,anaerobic conditions.It belongs to the orthorhombic system,space group P212121 with a = 5.786(5),b = 10.730(5),c = 19.722(5),C15H13NO2,Mr = 239.26,V = 1224.4(12)3,Z = 4 and Dc = 1.298 mg/m3.The final R = 0.0324 for 1627 observed reflections with Ⅰ 〉 2σ(Ⅰ) and Rw = 0.0826 for all data.The structure of compound 1 was determined by X-ray diffraction,NMR and HRMS. 展开更多
关键词 OXAZOLINE PHENOL 2-[4(s)-4 5-dihydro-4-phenyl-2-ozazolinyl c15H13NO2) crystal structure
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纳米C-S-H/PCE对蒸养UHPC力学性能增强机理研究 被引量:2
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作者 伍勇华 易昂 +2 位作者 何娟 匡玉峰 原毅冰 《硅酸盐通报》 CAS 北大核心 2024年第8期2797-2805,共9页
目前超高性能混凝土(UHPC)制品的力学性能有待进一步提升,采用纳米C-S-H/PCE对UHPC进行增强在理论上是一种可行的技术途径。本文研究了蒸养条件下掺入以聚羧酸(PCE)为分散剂的纳米水化硅酸钙(C-S-H/PCE)对UHPC力学性能的影响,通过测试... 目前超高性能混凝土(UHPC)制品的力学性能有待进一步提升,采用纳米C-S-H/PCE对UHPC进行增强在理论上是一种可行的技术途径。本文研究了蒸养条件下掺入以聚羧酸(PCE)为分散剂的纳米水化硅酸钙(C-S-H/PCE)对UHPC力学性能的影响,通过测试水化热、水化产物、微观形貌和孔结构等对其机理进行了分析。结果表明,掺入3.0%(质量分数)纳米C-S-H/PCE可以显著提高蒸养UHPC的抗压强度和抗折强度。掺入纳米C-S-H/PCE可以促进UHPC的早期水化,生成更多的水化硅酸钙(C-S-H)凝胶,使水化放热温峰增高,并缩短达到水化温峰的时间。掺入纳米C-S-H/PCE可有效改善蒸养UHPC的孔结构,在掺量为3.0%(质量分数)时总孔隙率最小,有害孔比例最低。该研究可为纳米C-S-H/PCE在蒸养UHPC中的应用提供参考。 展开更多
关键词 纳米c-s-H/PcE 超高性能混凝土 孔结构 水化放热 蒸汽养护
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纳米C-S-H-PCE对免蒸养高强混凝土性能的影响 被引量:6
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作者 付华 王鹏刚 +2 位作者 田砾 唐兴滨 赵铁军 《复合材料学报》 EI CAS CSCD 北大核心 2024年第1期333-347,共15页
针对蒸汽养护易引起混凝土初始损伤及耐久性差等问题。本文采用纳米水化硅酸钙-聚羧酸醚复合材料(n-C-S-H-PCE)制备免蒸养高强混凝土。通过水化热、低场核磁等试验研究了n-C-S-H-PCE对混凝土抗压强度、水化速率、孔径分布、自收缩及耐... 针对蒸汽养护易引起混凝土初始损伤及耐久性差等问题。本文采用纳米水化硅酸钙-聚羧酸醚复合材料(n-C-S-H-PCE)制备免蒸养高强混凝土。通过水化热、低场核磁等试验研究了n-C-S-H-PCE对混凝土抗压强度、水化速率、孔径分布、自收缩及耐久性的影响。结果表明:纳米水化硅酸钙(C-S-H)晶核为水化产物提供了成核位点,降低了成核的临界离子浓度K_(sp),诱导期和加速期显著提前,显著提高了混凝土早期抗压强度,1天混凝土抗压强度提高64%,且28天以后混凝土没有发生强度倒缩。掺入n-C-S-H-PCE后,混凝土基体孔径细化,凝胶孔和毛细孔比例均增加,导致混凝土自干燥过程中毛细孔负压增大,增大混凝土自收缩;然而,混凝土基体的最可几孔径和50~100 nm孔隙累计体积降低,提高了混凝土的抗氯离子侵蚀性能;孔径大于14 nm(临界孔径)的孔隙含量降低(由0.0287 mL/g降低到0.0156 mL/g),从而提高了混凝土的抗冻性能;此外,掺入n-C-S-H-PCE后,混凝土孔隙率降低,且随着矿粉掺量的增加,铝酸钙相和Ca2+的浓度降低,混凝土抗硫酸盐侵蚀能力提高。该研究为免蒸养、低收缩、高耐久、高强混凝土制备与应用提供了理论依据。 展开更多
关键词 纳米早强剂 免蒸养混凝土 孔结构 自收缩 耐久性 c-s-H-PcE
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Cu_(2-x)S@C纳米复合材料的制备及其电催化析氢性能
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作者 史桂梅 倪佳瑶 《沈阳师范大学学报(自然科学版)》 2024年第6期497-503,共7页
利用直流电弧法与硫化技术,设计构建了阳离子空位及核壳结构Cu_(2-x)S@C纳米复合材料,用于电催化析氢。研究表明:Cu_(2-x)S@C的阳离子空位和核壳协同作用优化了它们的氢吸附自由能,加速了水的电子转移和快速裂解,从而获得了对析氢反应... 利用直流电弧法与硫化技术,设计构建了阳离子空位及核壳结构Cu_(2-x)S@C纳米复合材料,用于电催化析氢。研究表明:Cu_(2-x)S@C的阳离子空位和核壳协同作用优化了它们的氢吸附自由能,加速了水的电子转移和快速裂解,从而获得了对析氢反应的高效催化活性。在电流密度为10 mA cm^(-2)时,Cu_(2-x)S@C的过电位低至99 mV,相应的Tafel斜率为65 mV。此外,Cu_(2-x)S@C在实验中表现出良好的稳定性。 展开更多
关键词 cu2-xs@c 阳离子空位 核壳结构 析氢反应
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